Eastern Iranian languages
Avestan is sometimes classified as Eastern Iranian, but is not assigned to a branch in recent classifications.
The Eastern Iranian area has been affected by widespread sound changes, e.g. t͡ʃ > ts.
Common to most Eastern Iranian languages is a particularly widespread lenition of the voiced stops *b, *d, *g. Between vowels, these have been lenited also in most Western Iranian languages, but in Eastern Iranian, spirantization also generally occurs in the word-initial position. This phenomenon is however not apparent in Avestan, and remains absent from Ormuri-Parachi.
The consonant clusters *ft and *xt have also been widely lenited, though again excluding Ormuri-Parachi, and possibly Yaghnobi.